1. Field of the Invention
The invention relates to systems for monitoring the playing of card games, and, particular, to systems for monitoring the playing of blackjack in casinos.
2. Description of the Related Art
Blackjack is a card game commonly played in casinos worldwide. The game is played by one or more players who compete individually against a dealer. The dealer represents the casino and performs the necessary game operational tasks. The object of the game is to achieve a total card value as close to but not greater than twenty-one.
The casino maintains a statistical advantage over the player since the dealer (i.e., casino) wins anytime the player's hand exceeds a total value of twenty-one regardless of the outcome of the dealer's hand. A knowledgeable player can reduce the casino's advantage by the proper execution of various play options available only to the player. Blackjack games are played with one or more decks of cards, and typically multiple rounds are completed before the cards are shuffled. Normally, blackjack games played with more than two decks of cards are dealt from a card-dispensing device commonly referred to as a shoe.
Blackjack is unique among games of chance in that the casino's statistical advantage continuously varies during play based on the number and types of cards removed. The removal of cards during each round of play affects the ratio of the high-value cards to the low-value cards remaining in the shoe. This ratio, which directly affects the casino's statistical advantage over the player, can vary widely during play for a number of reasons including an incomplete shuffling process. Specifically, the casino's advantage increases as the deck is depleted of high-value cards and decreases as the deck is depleted of low-value cards as described in "The Theory of Blackjack" by Griffin (Huntington Press, 1988). Periodically, enough low-valued cards will be removed from the deck to shift the advantage to the player.
A minority of players, commonly referred to as card counters, track the cards removed during play to determine the statistical condition of the remaining cards in the shoe. The card counter utilizes this information to adjust his bet level before each round of play, and also to determine the proper play strategy. For example, a card counter might place a small bet if the deck favored the casino and then increase the bet size when the deck favored the player. By altering bets in this manner, the card counter is able to achieve a statistical advantage over the casino. Some card counters, who are also known as shuffle trackers, can determine the statistical condition of selected card segments following completion of the shuffling process to adjust their bet size prior to play of the tracked segments.
Currently, casinos implement various active and passive countermeasures to limit their vulnerability to card counters and shuffle trackers. Active countermeasures are implemented as required and directed towards individual players whom the casino suspects are card counters. Active countermeasures may include one or more of the following: barring the individual from play, bet restrictions, and frequent shuffling. The active countermeasures provide some protection to the casino, but there are several weaknesses associated with these measures including: the period of time required to collect and analyze sufficient data to confirm that a suspected player is a card counter, the extensive commitment of casino resources required to continuously evaluate all blackjack players in the casino to detect the card counters, the inability of current methods for detecting card counters to detect shuffle trackers, and statutory prohibitions against some casinos from implementing one or more of the active countermeasures. Additionally, the active countermeasures introduce an element of confrontation between the casino patrons and employees that can detract from the entertainment aspects of the gaming industry.
To compensate for the weaknesses associated with the active countermeasures, casinos typically implement one or more passive countermeasures to limit the effectiveness of card counters. The passive countermeasures are continuously in effect and impact all players in the casino. These countermeasures may include one or more of the following: rule changes to shift the game's statistical advantage more in favor of the casino, reducing the number of rounds played between shuffles, restricting players from entering the game after the first round of play, and implementing complex shuffling patterns to foil shuffle trackers. The passive countermeasures are effective, but they also reduce the speed at which the game is played. Since the casino maintains a statistical advantage over the majority of players, the reduced game speed adversely impacts casino revenue. Also, the decreased game speed and rule changes tend to make the game less enjoyable for the majority of casino patrons.
Recently several computer-based technologies have been designed to enhance the casino's ability to identify card counters. One method described in "Surveillance Goes High-Tech--Spying on the Eye-in-the-Sky" by Arnold Snyder (Blackjack Forum, April 1997) requires the casino to manually enter the cards played, bet size, and playing options selected by an individual player into a computer software program that determines if the player is a card counter. Another technique described in U.S. Pat. No. 5,374,061 to Albrecht involves a system that identifies and assigns a count value to specially marked and coded cards as they are dealt from the card-dispensing shoe. The Albrecht system then displays the count value to assist casino personnel in determining whether a player's bet pattern is characteristic of a card counter. A similar, but more advanced system, described in "Better Safe Than Sorry" by Gros (Casino Player, September 1995) monitors both the count and variations in a player's bet pattern to determine if the bet pattern is characteristic of a card counter. A weakness with the latter system is that it requires use of a special dispensing shoe that is integral with a special blackjack table. The special system components are expensive and the fixed shoe location is uncomfortable for the dealers and a potential source of injury since the dealers are unable to properly position the shoe to account for varying body sizes.
The systems disclosed above enhance the casino's ability to detect card counters from among the other blackjack players and initiate active countermeasures against the suspected card counters. These systems, however, do not eliminate the remaining weaknesses associated with the active countermeasures and would require the casino to maintain one or more of the revenue-reducing passive countermeasures. Therefore, a need exists for a system that can limit the casino's vulnerability to card counters and shuffle trackers without adversely affecting casino revenue or the general public.